Process for preparing a molding-powder from coal or lignite.



' OFFICE.

ALFONS KoRTINe, or BERLIN-SfIDENDE, GERMANY.

PROCESS FOR PREPARING A MOLDING-POWDER FROM COAL 0R LIGNI'IE.

molding purposes. \Vhen grinding charcoal,

' coal or lignite and pouring a little of the obtained powder on water, it may be observed that the powder absorbs the moisture and consequently is not quite efficient for being used for the above purpose. In order that the powdered coal or lignite be wholly efficient for that purpose, it should be prepared in view of such use.

The novel process consists in satisfactorily distributing in the whole powdered mass the bituminous substances which are not uniformly deposited within the mass. With this object in view the coal is first ground and then dried. The resulting powder is then submitted to a high pressure. Owing to the heat occurring during said pressing, the resin paraffin or bitumen become soft. Said substances then fully and uniformly penetrate the powder. The high pressure to which the mass is submitted causes the agglomerating of same into a block or mass, so that it must be ground again to the degree of tenuity required for molding purposes. When the coal is highly bituminous, a strong heating will do, the bitumen thus becoming uniformly distributed within the mass. The so treated coal is no more hygrometric, that is to say it does no more absorb water and forms a perfect separating layer between the pattern or model and the molding sand.

It has been tried to prevent coke powder, infusorial earth or kieselguhr and other coal powders, cork powder, sawdust, lime, gypsum and the like, from being hygrometric or from absorbing water, by adding resins, fatty oils, waxes and the like, but such trials have'not given satisfactory results; a satisfactory molding powder has never been obtained. Practice has shown that at least fifty per cent. of the water repulsing substances should be ground, mixed or impregnated with the element in order to become Specification of Letters Patent.

Patented Mar. 6, 1917.

' No Drawing. Application filed May 29, 191 1, Serial No. 841,902. Renewed July 31, 1916. Serial No. 112,456.

antihygrometric, but a positive result has not yet been obtained. hen water is added repulsing substances such as oils, fats, fatty acids, waxes and the like, the element becomes pasty and cannot be used as molding powder because such powder would adhere to the mold, thus producing an effect just contrary to the desiredv one. Mixed with resins, the element is transformed in such a manner that it cannot be used as a molding powder, because when the liquid metal enters the mold, the resins become fluid and impregnate the sand, so that the shape of the mold changes and the gases are prevented from flowing through the sand. Furthermore the -manufacturing of such molding powders is very expensive and they have no advantages over the genuine lycopodium.

Furthermore the bituminous matter deposited m the coal by nature during thou.- sands of years contains good properties for molding powder and will not make the powder pasty.

Having now fully described my. said invention, what I claim and desire to secure by Letters Patent, is-

1. A process for preparing a molding powder which is not hygrometric, by means of coal and more especially by means of lignite, consisting in grinding the coal, in drying same, in submitting the resulting powder to high pressure, in order that by the heat developed by such pressure, the bituminous substances contained in the coal become uniformly distributed throughout the mass and in grinding the compressed agglomerated mass thus produced.

2. A process for preparing a molding powder which is not hygrometric, by means of coal and more especially by means of lignite, consisting in grinding the coal, in drying same, in submitting the resulting powder to high pressure and also to heat, in order that the bituminous substances contained in the coal become uniformly distributed throughout the mass and in grinding the compressed agglomerated mass thus produced.

In testimony whereof I have hereunto set my hand in presence of two witnesses.

ALF ONS KfjRTING.

Witnesses WOLDEMAR HAUPT, HENRY HASPER;

Copies of this patent may be obtained for five cents'each, by addressing the Commissioner of Patents, Washington, D. G. 

